APHIDS INJURIOUS TO ORCHAED FRUITS. 



17 



While principally injurious to the roots of the apple, its injuries 

 above ground are at times quite important. In orchards grown 

 under arid or semiarid conditions in the West it is decidedly 

 more troublesome than in the East, attacking the tree wherever 

 the bark is tender and sometimes infesting the stems of the leaves 

 and fruit. Its injuries 

 above ground often re- 

 sult in galls or swellings 

 similar to those on the 

 roots, and when the fruit 

 spurs are invaded (fig. 14) 

 the fruiting capacity of 

 the tree may be interfered 

 with seriously. The usual 

 contact sprays will be effec- 

 tive in destroying this pest 

 on the limbs and branches. 

 Its treatment on the roots 

 of the apple requires essen- 

 tially different methods, 

 which are not considered 

 in this bulletin. 



APPLE APHIDS OF MINOR IM- 

 PORTANCE. 



Several additional spe- 

 cies of aphids are found 

 upon the apple, but these 

 are at present of minor eco- 

 nomic importance. 



The potato aphis ^ has 

 been found feeding upon 

 apples occasionally in the 

 spring. Its normal winter 

 host appears to be the rose. 

 This form is very much 

 larger than the others men- 

 tioned, and the winged 

 forms, as well as the wingless one, is uniformly light greenish. 



Another species, which is slaty blue or black, with white bands 

 upon the legs, and often possesses white waxy tufts, occurs sometimes 

 upon the apple. This is the dock aphis.- The apple does not seem 

 to furnish suitable food to these insects, for after a few generations 

 they always leave the trees. 



-The woolly appl 

 spurs of apple. 



Injury to fruit 

 (Original.) 



^ Macrosiphum solanifoUac (Ashm.). 

 r85G9°— Bull. 804—17 3 



